johnb

M28/22 16V Euro engine
hi guys

first spot of bother with the engine strip down. my engine has a bridging water duct that joins the two heads together at the front of the engine (maybe the same on the USA models) also carries the thermostat etc.

it is held in place with four allen headed bolts, two either side. i have attempted to remove one, carefully, to be rewarded with just the bolts head. threaded part of bolt still in place.

do any of you guys have a trick to removing stubborn allen bolts (female hex bolts).

i will try heat and good 'ole WD40....ali, water, steel and 18 years of use have welded together! - joy.........NOT!

tips greatly appreciated.

regards
johnb

Jay Wellwood

I'd recommend removing the rest of the bolts and then removing the Cross over pipe.

Hopefully, when you remove the cross over pipe there will be enough threads exposed to be able to get a set of vise grips on the stub. Use plenty of penetrating oil/etc.

If nothing else, you can use a tungsten bit in a dremel tool to put a hole in the bolt and extract out the remnants.

Be careful as the heads (as you pointed out) are the receptacle for the offending bolts...screw them up and UHOH won't be enough....

hth-

John Veninger

I had rounded the hex head on one of my cam tower bolts. I drilled into the head of the hex and then hammered in a large "easy out". I was then able to back out the bolt.
Good luck.

Thom1

Hi John,

Use a good set of 3/8 inch drive ratchet driven allen wrenches, not the L shaped ones. There is a penetrant called PB B'laster that claims to be superior to WD40. I have used it with success.

HTH,
Good Luck, <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

Randy V

A common problem, also encountered on my '79.

My mechanic had to drill out the bolts then installed what he referred to as a 'time cert' - some sort of helicoil insert, however I've yet to hear this fastener terminology used elsewhere. Anyone else heard of these?

mojorizing

Hi John,

Consider these few pointers for stubborn bolts:

1) To remove remaining intact bolts, after soaking with PB blaster (good stuff) use new allen wrench and while applying torque, use hammer on wrench head to give slight blows (impact engineering).

2) Now that duct is removed,on remaining broken studs, use a vise grips that has it's teeth still intact on it's jaws or else you'll knurl the shank to nothing. Again apply hammer blows to top of stud. Use of locallized heat is fine but avoid stud because that will go plastic on you and break off. Apply heat to block...at this stage penetrant will smoke off...you can apply parrifin wax and it'll melt and wick into threads.

3)Last resort after steps 1 & 2 failed, grind broken bolt flush to surface of head and it'll leave a nice circle that you can use to center a punch on. Get drill, new bits , cutting oil and drill out center using progrssively larger drill till you're a little less then the minor dia. of bolt. As this procees is going on, the internal stress exerted by the rusty threads will be releived and it's likely that it'll break free. Use "easy-out" if not. Once broken bit is out, clean threads with tap to remove corrosion because you don't want to subject yourself with this again.

4)then have a cold beer...you deserve it!

Kevin

dr bob

Does anybody else use an "impact screwdriver" for stuff like this? This is the thing that looks like a fat screwdriver handle, has a square-drive end on it, takes allen bits, screwdriver bits, hex sockets, etc. Anything that has the matching square drive. I have them in both 3/8" and 1/2" drive. To use it, you rotate the handle in the direction you want the bolt/nut/screw to turn, then while holding the handle from turning, give it a whack with the hammer. The impact causes the bit to try and turn, seats it even more firmly in the allen capscrew or over the nut or whatever, and it also helps break free any stuck or corroded threads.

Impact screwdriver kits are available from Sears, Harbor Freight outlets (less than $20 IIRC), and plenty of other places. Anybody that's done work on aluminum motorcycle cases is familiar with the tool. Early Hondas and Yamahas, for instance, used fillister-head Phillips machine screws to hold the cases and covers on. The only way to get them out without stripping the soft heads is the impact screwdriver.


Randy: The "Time-Cert" is a solid threaded insert, as opposed to the "Heli-Coil' that is a wire insert. Heli-coils are OK, but the round wire doesn't have the strength that the sharp threads in the Time-Cert has. The Time-Cert is often installed with thread locker, and the end is distorted to keep it from coming out. Better industrial hardware stores carry these, along with an installation tool.


HTH!

Randy V

Thanks doc. You are a veritable wellspring of information!

Now, any ideas why they're called that? Perhaps it takes a lot of 'time' to in'sert' them <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" /> ?

Dozman

I have used PB Blaster. It is a phenominal(sp?) penetrating fluid. I reccomend it for every garage.

DOZMAN
'85 928 Auto, Black <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />

Tom

Make sure the socket head of the allen bolt is clean so the wrench can go in solidly.

John Struthers

John B.,
All above posts sound good.
Basically, it sounds like someone SHOULD have used anti-sieze compound during assembly and forgot.
Use liberal doses of penetrant on the remaining allens and the better halfs' hair dryer if you don't have a heat gun. To be brutally honest here, I would bet big bucks that you will have MORE breakage as you proceed. If you break another one, just keep on going and get it over with. Then procede to Kevin's plan with a few exceptions. 1.) If you can get a bolt out intact or have replacement bolts on hand lay it on the drill bit and get as close as you can to the TOTAL thread length remaining in the HOLE. Place a piece of tape or a depth marker on the drill bit so you don't go deeper than you want to, but go almost thru the bottom of the bolt.
2.)Either flatten the top of the remaining shank and center punch it. Or, at least leave a 1/4 inch. Reason being if you haven't done this before getting the pilot hole started and 'SQUARE'is a big issue. With some of the shank showing you can see if you are moving off center and adjust for it, or, flatten again and start over.
3. For some god forsaken reason or other every damned allen set I've run across seems to be cased/hardened. As a result in many cases as you increase drill bit size the cutting flutes will sometimes chip off. SO USE COBALT BITS!!!
And use a variable speed drill at MEDIUM SPEED with A lot of pressure. This will promote a better bite, reduce the chance of chipping those costly bits and generate less heat. Hopefully, you can pick the remains out with a machinist's scribe.
The aircraft industry has used locking, threaded inserts for years and would be my first choice if things get out of hand.
Last of all use anti-sieze compound when re-assembling.
HTH, LOL -lot's of luck.
John S. and Pattycakes
BTW Condolances are in order for your engine's demise. Wishing you a speedy and relatively inexpensive recovery.

johnb

hi guys

thanks for all those suggestions.

the trouble with those four bolts is that they are at an angle. if the heads go you cant just pull the assembly off. i ended up with two removed successfully, one broken off, and one with a rounded head (one either side - of course!)

in the end i had to cut thro the bolts between the head and the water manifold. leaving two flush bolts in the head....i'm hoping the machine shop can sort those!

oh joy!

regards
johnb